I have an app where reads and writes happen from different threads. Now, ideally, one would envision that I just replace the reads/writes with SSL_read/SSL_write. Now I know it is not as simple as that.
What exactly is the meaning of the SSL_ERROR_WANT_READ/WRITE errors?
If I get I get a WANT_READ from an SSL_read, I guess that means I need to read more data but no data is available on the socket yet. So I basically poll/select waiting for more data to arrive before I can reissue the SSL_read. Is that right?
If I get a WANT_WRITE from an SSL_read, does that mean that I need to do an SSL_write before I can reissue the SSL_read? And if so, what if I have no data to write? Can I just do an SSL_write() with an empty buffer? I'm assuming it is not application data that needs to be written, but some data contained in some internal ssl buffer?
If I get a WANT_WRITE from an SSL_write, does that mean the network buffer is full and I cannot write to the socket yet? In which case, I would just poll/select until the socket becomes writable and retry the SSL_write?
What if I get a WANT_READ from an SSL_write? Does that mean that I need to do an SSL_read before I can reissue the SSL_write? Again, I'm assuming the data that needs to be read is not application data. So can I just do an SSL_read giving it a 0 length buffer? Will this cause whatever data that is stored in the ssl buffers to be processed without reading data off the network (since I have a separate thread for reading and processing application data)?
Ed
